Image coding method, image decoding method, image coding apparatus, image decoding apparatus, and image coding and decoding apparatus

ABSTRACT

An image coding method of coding an image on a per coding unit basis, the method comprising: applying a frequency transform to luminance data and chrominance data of transform units in the coding unit including predetermined blocks each corresponding to one or more of the transform units; and coding the luminance data and the chrominance data to which the frequency transform has been applied to generate a bitstream in which the luminance data and the chrominance data are grouped on a per predetermined block basis.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 13/628,143,filed Sep. 27, 2012, which claims benefit of U.S. Provisional PatentApplication No. 61/540,048 filed Sep. 28, 2011. The entire disclosuresof the above-identified applications, including the specification,drawings and claims are incorporated herein by reference in theirentirety.

FIELD

The present disclosure relates to image coding methods of coding animage on a per block basis and image decoding methods of decoding animage on a per block basis.

BACKGROUND

Non-Patent Literature (NPL) 1 discloses a technique relating to an imagecoding method of coding an image (including a moving picture) on a perblock basis and an image decoding method of decoding an image on a perblock basis.

CITATION LIST Non Patent Literature

-   [NPL 1.] ISO/IEC 14496-10 “MPEG-4 Part 10 Advanced Video Coding”

SUMMARY Technical Problem

However, some conventional image coding methods and image decodingmethods include inefficient processes.

Thus, one non-limiting and exemplary embodiments herein provides animage coding method of efficiently coding an image, and an imagedecoding method of efficiently decoding an image.

Solution to Problem

The image coding method of coding an image on a per coding unit basisaccording to one embodiment of the present disclosure includes: applyinga frequency transform to luminance data and chrominance data oftransform units in the coding unit including predetermined blocks eachcorresponding to one or more of the transform units; and coding theluminance data and the chrominance data to which the frequency transformhas been applied to generate a bitstream in which the luminance data andthe chrominance data are grouped on a per predetermined block basis.

These general and specific aspects may be implemented using a system, anapparatus, an integrated circuit, a computer program, or anon-transitory computer-readable recording medium such as a CD-ROM, orany combination of systems, apparatuses, methods, integrated circuits,computer programs, or computer-readable recording media.

Additional benefits and advantages of the disclosed embodiments will beapparent from the Specification and Drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the Specification and Drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

Advantageous Effects

The image coding method and the image decoding method according to oneor more exemplary embodiments or features disclosed herein provide amethod of efficiently coding or decoding an image.

BRIEF DESCRIPTION OF DRAWINGS

These and other advantages and features will become apparent from thefollowing description thereof taken in conjunction with the accompanyingDrawings, by way of non-limiting examples of embodiments disclosedherein,

FIG. 1 illustrates a conventional bitstream.

FIG. 2 is a block diagram illustrating a configuration of the imagecoding apparatus according to the first embodiment.

FIG. 3 illustrates the bitstream according to the first embodiment.

FIG. 4 is a flow chart illustrating the coding operation according tothe first embodiment.

FIG. 5 illustrates the bitstream according to a variation of the firstembodiment,

FIG. 6 is a flow chart illustrating the coding operation according to avariation of the first embodiment.

FIG. 7 is a block diagram illustrating a configuration of the imagecoding apparatus according to the second embodiment.

FIG. 8 illustrates the bitstream according to the second embodiment.

FIG. 9 is a flow chart illustrating the coding operation according tothe second embodiment.

FIG. 10 illustrates the division and allocation of processing for themultiple computing units according to the second embodiment.

FIG. 11 is a block diagram illustrating a configuration of the imagedecoding apparatus according to the third embodiment.

FIG. 12 is a flow chart illustrating the decoding operation according tothe third embodiment.

FIG. 13 is a block diagram illustrating a configuration of the imagedecoding apparatus according to the fourth embodiment.

FIG. 14 is a flow chart illustrating the decoding operation according tothe fourth embodiment.

FIG. 15A is a block diagram illustrating a configuration of the imagecoding apparatus according to the fifth embodiment.

FIG. 15B is a flow chart illustrating the coding operation according tothe fifth embodiment.

FIG. 16A is a block diagram illustrating a configuration of the imagedecoding apparatus according to the fifth embodiment.

FIG. 16B is a flow chart illustrating the decoding operation accordingto the fifth embodiment.

FIG. 17 An overall configuration of a content providing system forimplementing content distribution services.

FIG. 18 An overall configuration of a digital broadcasting system.

FIG. 19 A block diagram illustrating an example of a configuration of atelevision.

FIG. 20 A block diagram illustrating an example of a configuration of aninformation reproducing/recording unit that reads and writes informationfrom and on a recording medium that is an optical disk.

FIG. 21 An example of a configuration of a recording medium that is anoptical disk.

FIG. 22A An example of a cellular phone.

FIG. 22B A block diagram showing an example of a configuration of acellular phone.

FIG. 23 A structure of multiplexed data.

FIG. 24 How to multiplex each stream in multiplexed data.

FIG. 25 How to store a video stream in a stream of PES packets in moredetail.

FIG. 26 A structure of TS packets and source packets in the multiplexeddata.

FIG. 27 A data structure of a PMT,

FIG. 28 An internal structure of multiplexed data information.

FIG. 29 An internal structure of stream attribute information.

FIG. 30 Steps for identifying video data.

FIG. 31 An example of a configuration of an integrated circuit forimplementing the moving picture coding method and the moving picturedecoding method according to each of embodiments.

FIG. 32 A configuration for switching between driving frequencies.

FIG. 33 Steps for identifying video data and switching between drivingfrequencies.

FIG. 34 An example of a look-up table in which video data standards areassociated with driving frequencies.

FIG. 35A A diagram showing an example of a configuration for sharing amodule of a signal processing unit.

FIG. 35B A diagram showing another example of a configuration forsharing a module of the signal processing unit.

DESCRIPTION OF EMBODIMENTS

(Underlying Knowledge Forming Bests of the Present Disclosure)

In relation to the technique relating to an image coding apparatus forcoding an image on a per block basis and an image decoding apparatus fordecoding an image on a per block basis disclosed in the Backgroundsection, the inventors have found the following problem:

Recent years have seen rapid advancement in digital video equipmenttechnology. The ability to compress a video signal (a plurality ofpictures arranged in a time series) input from a video camera or atelevision tuner and store the compressed signal on a recordable mediumsuch as a DVD or hard disk has become commonplace.

When a video signal is coded, image data is generally demultiplexer)into luminance information (Y), first chrominance information (U), andsecond chrominance information (V). A frequency transform is applied toeach of these, and the coefficient value obtained as a result is codedusing a coding technique such as variable length coding or arithmeticcoding.

Even more specifically, a single image is partitioned into coding units(hereinafter referred to as CU), a CU is further partitioned intotransform units (hereinafter referred to as TU), then a frequencytransform is applied to each of the Y, U, and V in a TU, A bitstream isthen generated by combining the Y, U, and V coding results. Moreover, inthe decoding, the coefficient value of each of the Y, U, and V isdecoded from the bitstream, and image information for each of the Y, U,and V is obtained from the coefficient values by inverse transformation.

It is to be noted that a CU is a unit of data for coding an image whichcorresponds to a macroblock according to the video coding standardsH.264/AVC and MPEG-4 AVC (see NPL 1). The CU is included in a picture orin a slice within a picture. A largest coding unit (hereinafter referredto as LCU) is a square of a predetermined fixed size. The CU is a squaresmaller than the predetermined fixed size. Two CUs in the same pictureor in the same slice may be squares of different sizes.

For example, each of the four blocks defined by partitioning a square ofa predetermined fixed size in a picture or slice into four parts may bedesignated as the CU. Moreover, among a plurality of hierarchical blocksdefined by partitioning a square of a predetermined fixed size into fourparts in multiple stages, the lowest hierarchical block may bedesignated as the CU. When a square of a predetermined fixed size is notpartitioned into four parts, the LCU may be designated as the CU. Animage is coded on a per CU basis and a bitstream is generated inaccordance with the above described designations.

In the conventional example shown in FIG. 1, for each CU, each of the Y,U, and V are arranged in sequence and a bitstream is generated. In FIG.1, Yn is Y information for TUn, Un is U information for TUn, and Vn is Vinformation for TUn. Moreover, FIG. 1 is an example of a 4:2:0 format,meaning the number of pixels in U and V are one-forth that of Y.

However, in the conventional bitstream structure, since the U and Vbitstreams cannot be outputted until every Y in the CU is coded andoutputted in a bitstream, even if the situation allowed for a bitstreamof U or V to be outputted ahead of a portion of Y in the CU, it wouldnot be possible to do so. In other words, buffering is required. Using(C) in FIG. 1 to explain, the bitstream for U0 cannot be outputted untilthe bitstream for Y9 is outputted, requiring the information on U0 to beplaced in the buffer memory or register. For this reason, a problemarises in which a larger buffer memory or register is required.

Moreover, in decoding as well, while video cannot be outputted until Y,U, and V are decoded, U and V cannot be decoded until every Y in the CUis decoded. This means that buffering the Y decoding result isnecessary. Using (C) in FIG. 1 to explain, the T0 block cannot beoutputted to video until V0 is decoded, requiring Y0 to Y9 and U0 to U9to be placed in the buffer memory or register.

In order to solve the above described problem, the image coding methodof coding an image on a per coding unit basis according to oneembodiment of the present disclosure includes: applying a frequencytransform to luminance data and chrominance data of transform units inthe coding unit including predetermined blocks each corresponding to oneor more of the transform units; and coding the luminance data and thechrominance data to which the frequency transform has been applied togenerate a bitstream in which the luminance data and the chrominancedata are grouped on a per predetermined block basis.

With this, U and V bitstreams can be outputted even before thebitstreams for every Y in the CU have been outputted, therebyeliminating the need to buffer U and V and allowing for a reduced buffermemory or register.

For example, each of the predetermined blocks may correspond totransform units in a block of a predetermined size, or to a transformunit of a size greater than or equal to the predetermined size, and inthe coding, the luminance data and the chrominance data may be coded togenerate the bitstream in which the luminance data and the chrominancedata are grouped on a per predetermined block basis.

With this, the Y, U, and V are arranged in a bitstream on a perappropriate data unit basis, resulting in increased processingefficiency.

Moreover, for example, in the applying: the frequency transform may beapplied to the luminance data on a per transform unit basis; when atotal number of pixels of the chrominance data and a total number ofpixels of the luminance data are equal, the frequency transform may beapplied to the chrominance data on a per transform unit basis; and whenthe total number of pixels of the chrominance data is less than thetotal number of pixels of the luminance data, the frequency transformmay be applied to the chrominance data on a per predetermined blockbasis.

With this, a frequency transform is applied on a per data unit basis tothe Y, U, and V, the data unit being a data unit appropriate for thenumber of pixels. As a result, processing efficiency increases.

Moreover, for example, in the applying, from among the chrominance dataof the transform units in the coding unit, chrominance data of transformunits in a block of a size that is smaller than or equal to thepredetermined size may be combined, and the frequency transform may beapplied to the combined chrominance data in one frequency transform.

With this, the data unit for transformation can be kept from becomingtoo small. As a result, it is not necessary to provide a small transformcircuit. Moreover, in contrast to a case in which Y had to be madelarger than the smallest TU size in an effort to keep U or V from beingsmaller than the smallest TU, with this configuration, Y can be made tobe the smallest TU size, resulting in increased coding efficiency.

Moreover, for example, in the applying, when a size of one of thetransform units is a predetermined smallest size and in the transformunit a total number of pixels of chrominance data is less than a totalnumber of pixels of luminance data, from among the chrominance data ofthe transform units in the coding unit, chrominance data of transformunits in a block including the transform unit may be combined, and thefrequency transform may be applied to the combined chrominance data inone frequency transform.

With this, even when the TU size is the smallest TU size and the numberof pixels in U or V is less than the number of pixels in Y, as is thecase in a 4:2:0 or 4:2:2 format, neither U nor V are smaller than thesmallest TU size. As a result, it is not necessary to provide atransform circuit that is smaller than the smallest TU. Moreover, incontrast to a case in which Y had to be made larger than the smallest TUsize in an effort to keep U or V from being smaller than the smallestTU, with this configuration, Y can be made to be the smallest TU size,resulting in increased coding efficiency.

Moreover, for example, in the coding, luminance data and chrominancedata of transform units in one of the predetermined blocks may be codedto generate the bitstream in which, in the predetermined block, thechrominance data of all the transform units follows the luminance dataof all the transform units.

With this, U and V follow Y, and this sequence is maintained. As aresult, it is not necessary to take into consideration switching thissequence, Consequently, it is possible to reduce the complexity of theimage processing.

Moreover, for example, each of the predetermined blocks may correspondto transform units in a block of a predetermined size, or to a transformunit of a size greater than or equal to the predetermined size, in theapplying, the frequency transform may be applied to the luminance dataand the chrominance data on a per transform unit basis, and in thecoding, the luminance data and the chrominance data may be coded togenerate the bitstream in which the luminance data and the chrominancedata are grouped on a per predetermined block basis.

With this, it is possible to combine and processes the Y, U, and V intorespective multiple blocks and to input the input images in nearly onebatch for each of the Y, U and V, thereby increasing data transferefficiency. Moreover, variation in the number of pixels in a YUV set canbe suppressed, and the computing unit operating rate can be increasedwhen parallel processing YUV data units with multiple computing units.

Moreover, for example, each of the predetermined blocks may correspondto a different one of the transform units, in the applying, thefrequency transform may be applied to the luminance data and thechrominance data on a per transform unit basis, and in the coding, theluminance data and the chrominance data may be coded to generate thebitstream in which the luminance data and the chrominance data aregrouped on a per transform unit basis.

With this, the Y, U, and V are arranged in a bitstream in simple andappropriate data units. As a result, processing efficiency is increased.

Moreover, the image decoding method of decoding an image on a per codingunit basis according to one embodiment of the present disclosure mayinclude: decoding luminance data and chrominance data of transform unitsin the coding unit including predetermined blocks each corresponding toone or more of the transform units, the decoding including obtaining abitstream, and the luminance data and the chrominance data being data towhich a frequency transform has been applied and which has been codedand grouped in the bitstream on a per predetermined block basis; andapplying an inverse frequency transform to the decoded luminance dataand the decoded chrominance data.

With this, U and V can be decoded even before every Y in the CU has beendecoded, thereby eliminating the need to buffer the U and V decodingresult and allowing for a reduced buffer memory or register.

For example, each of the predetermined blocks may correspond totransform units in a block of a predetermined size, or to a transformunit of a size greater than or equal to the predetermined size, and inthe decoding, the bitstream in which the luminance data and thechrominance data are grouped on a per predetermined block basis may beobtained, and the luminance data and the chrominance data are decoded.

With this, a bitstream in which the Y, U, and V are arranged inappropriate data units is used. As a result, processing efficiency isincreased.

Moreover, for example, in the applying: the inverse frequency transformmay be applied to the luminance data on a per transform unit basis; whena total number of pixels of the chrominance data and a total number ofpixels of the luminance data are equal, the inverse frequency transformmay be applied to the chrominance data on a per transform unit basis;and when the total number of pixels of the chrominance data is less thanthe total number of pixels of the luminance data, the inverse frequencytransform may be applied to the chrominance data on a per predeterminedblock basis.

With this, an inverse frequency transform is applied per data unit tothe Y, U, and V, the data unit being a data unit appropriate for thenumber of pixels. As a result, processing efficiency is increased.

Moreover, for example, in the applying, the inverse frequency transformmay be applied to, from among the chrominance data of the transformunits in the coding unit, chrominance data of transform units in a blockof a size that is smaller than or equal to the predetermined size in oneinverse frequency transform.

With this, the data unit for transformation becoming too small can beavoided. As a result, it is not necessary to provide a small inversetransform circuit. Moreover, in contrast to a case in which Y had to bemade larger than the smallest TU size in an effort to keep U or V frombeing smaller than the smallest TU, with this configuration, Y can bemade to be the smallest TU size, resulting in increased codingefficiency.

Moreover, for example, in the applying, when a size of one of thetransform units is a predetermined smallest size and in the transformunit a total number of pixels of the chrominance data is less than atotal number of pixels of the luminance data, the inverse frequencytransform may be applied to, from among the chrominance data of thetransform units in the coding unit, chrominance data of transform unitsin a block including the transform unit in one inverse frequencytransform.

With this, even when the TU size is the smallest TU size and the numberof pixels in U or V is less than the number of pixels in Y, as is thecase in a 4:2:0 or 4:2:2 format, neither U nor V are smaller than thesmallest TU size. As a result, it is not necessary to provide an inversetransform circuit that is smaller than the smallest TU. Moreover, incontrast to a case in which Y had to be made larger than the smallest TUsize in an effort to keep U or V from being smaller than the smallestTU, with this configuration, Y can be made to be the smallest TU size,resulting in increased coding efficiency.

Moreover, for example, in the decoding, the bitstream may be obtained inwhich, in one of the predetermined blocks, chrominance data of alltransform units follows luminance data of all the transform units, andthe luminance data and the chrominance data of the transform units inthe predetermined block may be decoded.

With this, U and V follow Y, and this sequence is maintained. As aresult, it is not necessary to take into consideration switching thissequence. Consequently, it is possible to reduce the complexity of theimage processing.

For example, each of the predetermined blocks may correspond totransform units in a block of a predetermined size, or to a transformunit of a size greater than or equal to the predetermined size, in thedecoding, the bitstream in which the luminance data and the chrominancedata are grouped on a per predetermined block basis may be obtained, andthe luminance data and the chrominance data are decoded, and in theapplying, the inverse frequency transform may be applied to theluminance data and the chrominance data on a per transform unit basis.

With this, it is possible to combine and processes the Y, U, and V intorespective multiple blocks and to output the output images in nearly onebatch for each of the Y, U and V, thereby increasing data transferefficiency. Moreover, variation in the number of pixels in a YUV set canbe suppressed, and the computing unit operating rate can be increasedwhen parallel processing YUV data units with multiple computing units.

Moreover, for example, each of the predetermined blocks may correspondto a different one of the transform units, in the decoding, thebitstream in which the luminance data and the chrominance data aregrouped on a per transform unit basis may be obtained, and the luminancedata and the chrominance data may be decoded, and in the applying, theinverse frequency transform may be applied to the luminance data and thechrominance data on a per transform unit basis.

With this, a bitstream in which the Y, U, and V are arranged in simpleand appropriate data units is used. As a result, processing efficiencyis increased.

It is to be noted that these general and specific aspects may beimplemented using a system, an apparatus, an integrated circuit, acomputer program, or a non-transitory computer-readable recording mediumsuch as a CD-ROM, or any combination of systems, apparatuses, methods,integrated circuits, computer programs, or computer-readable recordingmedia.

Hereinafter, certain exemplary embodiments are described in greaterdetail with reference to the accompanying Drawings. Each of theexemplary embodiments described below shows a general or specificexample. The numerical values, shapes, materials, structural elements,the arrangement and connection of the structural elements, steps, theprocessing order of the steps etc. shown in the following exemplaryembodiments are mere examples, and therefore do not limit the scope ofthe appended Claims and their equivalents. Therefore, among thestructural elements in the following exemplary embodiments, structuralelements not recited in any one of the independent claims are describedas arbitrary structural elements.

Embodiment 1 (Configuration)

FIG. 2 shows a configuration of the image coding apparatus according tothe first embodiment. The image coding apparatus partitions the inputimages into CUs and TUs, performs a transform process on and codes theY, U, and V, then outputs a bitstream thereof. The image codingapparatus includes a CU partitioning unit 101, a TU partitioning unit102, a YUV demultiplexing unit 103, an adjacent block combining unit104, a Y transforming unit 105, a U transforming unit 106, a Vtransforming unit 107, a coder 108, and a YUV switching unit 109.

The CU partitioning unit 101 inputs an image and partitions the imageaccording to a specified CU size. The TU partitioning unit 102partitions the CU according to a specified TU size. The YUVdemultiplexing unit 103 demultiplexes the TU into Y, U, and Vcomponents. In this embodiment, the image format is 4:2:0. In thisformat, the size of the U component and the V component are one-fourththe size of the Y component.

The adjacent block combining unit 104 combines adjacent U blocks andcombines adjacent V blocks according to TU size and the smallest TUsize. The Y transforming unit 105, the U transforming unit 106, and theV transforming unit 107 each perform a transform process on Y, U, and V,respectively. The coder 108 codes the transformed data and outputs abitstream of the transformed data. The YUV switching unit 109 switchesinput to the coder 108 according to the TU size.

FIG. 3 shows an example of a bitstream. When the CU size and the TU sizeare the same as in (A) this is the same as in the conventional exampleshown in FIG. 1, but when the TU size is smaller than the CU as in (B),this is different from the conventional example. In this case, Y1, U1,and V1 in the TU1 are coded after the Y0, U0, and V0 in the TU0.Moreover, when the TU size is the smallest TU size as is TU0 in (C), theformat is 4:2:0. As such, the U blocks and the V blocks are smaller thanthe smallest TU size. In this case, the respective U blocks and V blocksin TU0, TU1, TU2, and TU3 are combined, and transformation and coding isperformed on the combined blocks, whereby a bitstream is generated.

(Operation)

Next, the coding flow will be described with reference to FIG. 4. First,the CU partitioning unit 101 partitions the input image according to thespecified CU size, generates the CU, and outputs the CU to the TUpartitioning unit 102 (S101). The TU partitioning unit 102 partitionsthe CU according to a specified TU size, and outputs the result to theYUV demultiplexing unit 103 (S102). It is to be noted that the imagecoding apparatus repeats the CU processes (S102 to S116) a number oftimes that there are CUs in a single image since the processes areperformed on all CUs within a single image.

Next, the YUV demultiplexing unit 103 demultiplexes the TU into Y, U,and V components (S103). In this embodiment, the image format is 4:2:0.in this format, the size of the U component and the V component areone-fourth the size of the Y component. The demultiplexed Y componentsare outputted to the Y transforming unit 105, and the U components and Vcomponents are outputted to the adjacent block combining unit 104. It isto be noted that the image coding apparatus repeats the TU processes(S103 to S116) a number of times that there are TUs in a single CU sincethe processes are performed on all TUs within a single CU.

Next, the YUV switching unit 109 switches the input to the coder 108 tobe the output of the Y transforming unit 105 (S104). The Y transformingunit 105 performs the transform process on Y, and outputs thetransformed result to the coder 108 (S105). The coder 108 codes thetransformed Y and outputs a bitstream of the coded Y (S106).

Next, the adjacent block combining unit 104 determines whether thecurrent U block to be transformed and coded is already combined withanother U block (S107). If the U block is already combined with anotherU block (yes in S107), the processes for the U block and the V block(S108 to S116) are skipped. If the U block is not already combined withanother U block (no in S107), the next process (S108) is performed.

Specifically, when the U block is not already combined with another Ublock (no in S107), the adjacent block combining unit 104 determineswhether the size of the U in the TU is smaller than the smallest TU size(S108). If the size of the U is smaller than the smallest TU size (yesin S108), the U block combining process is performed (S109). If the sizeof the U is not smaller than the smallest TU size (no in S108), theadjacent block combining unit 104 outputs the current U block and thecurrent V block to be transformed and coded to the U transforming unit106 and the V transforming unit 107, respectively. A YUV switchingprocess (S111) is then performed.

If the size of the U is smaller than the smallest TU size (yes in S108),the adjacent block combining unit 104 combines the current U block to betransformed and coded with three U blocks that are to the right, bottom,and bottom-right thereof, and generates and outputs a four-blockcombined U block to the U transforming unit 106 (S109). The adjacentblock combining unit 104 then combines the current V block to betransformed and coded with three V blocks that are to the right, bottom,and bottom-right thereof, and generates and outputs a four-blockcombined V block to the V transforming unit 107 (S110).

Next, the YUV switching unit 109 switches the input to the coder 108 tobe the output of the U transforming unit 106 (S111). The U transformingunit 106 performs the transform process on U, and outputs thetransformed result to the coder 108 (S112). The coder 108 codes thetransformed U and outputs a bitstream of the coded U (S113).

Next, the YUV switching unit 109 switches the input to the coder 108 tobe the output of the V transforming unit 107 (S114). The V transformingunit 107 performs the transform process on V, and outputs thetransformed result to the coder 108 (S115). The coder 108 codes thetransformed V and outputs a bitstream of the coded V (S116).

(Result)

According to the first embodiment, U and V bitstreams can be outputtedeven before the bitstreams for every Y in the CU have been outputted,thereby eliminating the need to buffer U and V and allowing for areduced buffer memory or register.

Moreover, even when the TU size is the smallest TU size and the numberof pixels in U or V is less than the number of pixels in Y, as is thecase in a 4:2:0 or 4:2:2 format, neither U nor V are smaller than thesmallest TU size. As a result, it is not necessary to provide atransform circuit that is smaller than the smallest TU. Moreover, incontrast to a case in which Y had to be made larger than the smallest TUsize in an effort to keep U or V from being smaller than the smallestTU, with this configuration, Y can be made to be the smallest TU size,resulting in increased coding efficiency.

It is to be noted that in the first embodiment a 4:2:0 format is used,but a 4:2:2, 4:4:4, or different format may be used.

Moreover, in the first embodiment, the CU size and the TU size are inputexternally. However, an optimum size may be used which is computed bycalculating the coding efficiency of the size of multiple or allpatterns internally in the apparatus.

Moreover, in the first embodiment, combined U and combined V blocks areplaced directly after the bitstream for the Y of the TU to theupper-left in the combined TU, as shown in FIG. 3. However, the combinedU and combined V blocks may be placed directly after the bitstream forthe Y of the TU to the bottom-right in the combined TU, as shown in FIG.5. In this case, the operation shown in FIG. 4 is modified to theoperation shown in FIG. 6, for example.

Specifically, as is shown in FIG. 6, when the size of the U in the TU islarger than or equal to the smallest TU size (no in S108), the U and Vblocks are processed as is (S111 to S116).

When the size of the U in the TU is smaller than the smallest TU size(yes in S108) and the TU to be processed is the fourth TU (yes in S120),the U block combining process (S109) and the V block combining process(S110) are performed. Here, the fourth TU corresponds to the fourth TUto be processed among the four smallest TUs, such as TU3 or TU9 in FIG.5.

In the U block combining process (S109), the adjacent block combiningunit 104 combines the U block to be processed with the three U blocksthat are to the left, top, and top-left thereof, and generates afour-block combined U block. Moreover, in the U block combining process(S110), the adjacent block combining unit 104 combines the V block to beprocessed with the three V blocks that are to the left, top, andtop-left thereof, and generates a four-block combined V block. The U andV blocks are then processed (S111 to S116).

When the size of the U in the TU is smaller than the smallest TU size(yes in S108) and the TU to be processed is not the fourth TU (no inS120), the processing of the U and V blocks (S111 to S116) is skipped.Other operations are the same as those shown in FIG. 4. In this way, thebitstream shown in FIG. 5 is output as a result of the operation beingmodified.

In FIG. 5, U and V follow Y, and this sequence is maintained. As aresult, it is not necessary to take into consideration switching thesequence of Y, U, and V. Consequently, it is possible to reduce thecomplexity of the image processing. In FIG. 6, it is determined whetheror not the TU to be processed is the fourth TU, but it may be determinedwhether or not the TU to be processed is the last TU to be combined.When the TU to be processed is the last TU to be combined, the combiningprocesses (S109 and S110) may be performed.

Moreover, in the first embodiment, four blocks are combined, but t isacceptable if two blocks are combined in a 4:2:2 format. For example,two blocks horizontally adjacent to each other may be combined. Then,among the two blocks, it is acceptable if the combining process isperformed on the first or second block to be processed.

Furthermore, the processing performed in the first embodiment may beexecuted with software. The software may be distributed via downloading.Moreover, the software may be stored on a storage medium such as aCD-ROM and distributed. It is to be noted that this applies to all otherembodiments throughout the Description as well.

Embodiment 2 (Configuration)

FIG. 7 shows a configuration of the image coding apparatus according tothe second embodiment. Here, only the YUV switching unit 109 isdescribed since the YUV switching unit 109 is different from the firstembodiment.

The YUV switching unit 109 switches input to the coder 108 according toTU size and the specified smallest block size. Specifically, the YUVswitching unit 109 switches the input to the coder 108 on a per dataunit basis to be either Y, U, or V, the data unit being the larger ofthe TU size and the smallest block size. In the second embodiment, thesmallest block size is a predetermined, fixed size that is larger thanthe smallest TU size.

FIG. 8 shows an example of a bitstream. When the TU size is not smallerthan the smallest block size such as in (A) or (B), the bitstream is thesame as the first embodiment, but when the TU size is smaller than thesmallest block size such as in (C), this is different from the firstembodiment. Here, for TU0 through TU3, first U0 through U3 and V0through V3 are coded after Y0 through Y3, followed by Y4, U4, and V4 ofTU4.

(Operation)

Next, the coding flow is described with reference to FIG. 9. First, theCU partitioning unit 101 partitions the input image according to thespecified CU size, generates the CU, and outputs the CU to the TUpartitioning unit 102 (S201). The TU partitioning unit 102 partitionsthe CU according to a specified TU size, and outputs the result to theYUV demultiplexing unit 103 (S202). It is to be noted that the imagecoding apparatus repeats the CU processes (S202 to S222) a number oftimes that there are CUs in a single image since the processes areperformed on all CUs within a single image.

Next, the YUV switching unit 109 determines whether the TU size issmaller than the smallest block size (S203). If the TU size is smallerthan the smallest block size (yes in S203), a coding determinationprocess (S213) is performed. If the TU size is not smaller than thesmallest block size (no in S203), a YUV switching process (S204) isperformed. It is to be noted that the image coding apparatus repeats theTU processes (S203 to S222) a number of times that there are TUs in asingle CU since the processes are performed on all TUs within a singleCU.

If the TU size is not smaller than the smallest block size (no in S203),the YUV switching unit 109 switches the input to the coder 108 to be theoutput of the Y transforming unit 105 (S204). The Y transforming unit105 performs the transform process on Y, and outputs the transformedresult to the coder 108 (S205). The coder 108 codes the transformed Yand outputs a bitstream of the coded Y (S206).

Next, the YUV switching unit 109 switches the input to the coder 108 tobe the output of the U transforming unit 106 (S208). The U transformingunit 106 performs the transform process on U, and outputs thetransformed result to the coder 108 (S208). The coder 108 codes thetransformed U and outputs a bitstream of the coded U (S209).

Next, the YUV switching unit 109 switches the input to the coder 108 tobe the output of the V transforming unit 107 (S210). The V transformingunit 107 performs the transform process on V, and outputs thetransformed result to the coder 108 (S211). The coder 108 codes thetransformed V and outputs a bitstream of the coded V (S212).

If the TU size is smaller than the smallest block size (yes in S203),the YUV switching unit 109 determines whether the current Y block, Ublock, and V block to be transformed and coded are already coded (S213).If already coded (yes in S213), the processes for the TU (S214 to S222)are skipped, if not already coded (no in S213), a YUV switching process(S214) is performed.

Specifically, if the Y, U, and V blocks are not already coded (no inS213), the YUV switching unit 109 switches the input to the coder 108 tobe the output of the Y transforming unit 105 (S214). The Y transformingunit 105 performs the transform process on Y, and outputs thetransformed result to the coder 108 (S215). It is to be noted that theimage coding apparatus repeats the Y processes (S215 to S216) a numberof times that there are TUs in a smallest block since the processes areperformed on all TUs within the smallest block. The coder 108 codes thetransformed Y and outputs a bitstream of the coded Y (S216).

Next, the YUV switching unit 109 switches the input to the coder 108 tobe the output of the U transforming unit 106 (S217). The U transformingunit 106 performs the transform process on U, and outputs thetransformed result to the coder 108 (S218). It is to be noted that theimage coding apparatus repeats the U processes (S218 to S219) a numberof times that there are TUs in a smallest block since the processes areperformed on all TUs within the smallest block. The coder 108 codes thetransformed U and outputs a bitstream of the coded U (S219).

Next, the YUV switching unit 109 switches the input to the coder 108 tobe the output of the V transforming unit 107 (S220). The V transformingunit 107 performs the transform process on V, and outputs thetransformed result to the coder 108 (S221). It is to be noted that theimage coding apparatus repeats the V processes (S221 to S222) a numberof times that there are TUs in a smallest block since the processes areperformed on all TUs within the smallest block. The coder 108 codes thetransformed V and outputs a bitstream of the coded V (S222).

(Result)

With the second embodiment, it is possible to combine and processes theY, U, and V into respective multiple blocks and to input the inputimages in nearly one batch for each of the Y, U and V, therebyincreasing data transfer efficiency. This is especially effective in asystem which uses high-speed memory such as cache memory, since thecapability to process Y or U or V in sequence leads to an improvement incache memory hit ratio. Moreover, variation in the number of pixels in aYUV set can be suppressed, and the computing unit operating rate can beincreased when parallel processing YUV data units with multiplecomputing units. A specific example will be given with reference to FIG.10.

FIG. 10 illustrates a system in which four computing units are used toprocess the YUV set wherein the YUV set is divided and allocated to thecomputing units A through D in order from the beginning. When the YUVare consistently arranged by TU size such as in (A), the processing loadrequired of the computing unit C and the computing unit D is smallcompared to that of the computing unit A and the computing unit B.Consequently, the operating rate of the computing unit C and thecomputing unit D decreases. However, by arranging the YUV per data unitof the larger of the smallest block size and the TU size such as in thesecond embodiment, the processing load is equal for each of thecomputing units A through D, thereby increasing the operating rate ofthe computing unit C and the computing unit D.

Embodiment 3 (Configuration)

FIG. 11 shows a configuration of the image decoding apparatus accordingto the third embodiment. The image decoding apparatus is used whendecoding the bitstream coded by the image coding apparatus described inthe first embodiment. The image decoding apparatus includes a decoder301, a Y inverse transforming unit 302, a U inverse transforming unit303, a V inverse transforming unit 304, a YUV combining unit 305, a TUcombining unit 306, a CU combining unit 307, a YUV switching unit 308,and an adjacent block partitioning unit 309.

The decoder 301 decodes a bitstream and outputs the transformed YUVdata. The Y inverse transforming unit 302, the U inverse transformingunit 303, and the V inverse transforming unit 304 each perform aninverse transform process on Y, U, and V, respectively. The YUVcombining unit 305 combines the Y, U, and V components. In thisembodiment, the image format is 4:2:0. In this format, the size of the Ucomponent and the V component are one-fourth the size of the Ycomponent.

The TU combining unit 306 combines the TU in the CU according to aspecified TU size, and generates the CU. The CU combining unit 307combines the CU in an image according to a specified CU size andgenerates the image. The YUV switching unit 308 switches the outputdestination of the decoder 301 according to the TU size. The adjacentblock partitioning unit 309 partitions the inverse transforming resultfor each of the U and V four ways according to the TU size and thesmallest TU size.

(Operation)

Next, the decoding flow will be described with reference to FIG. 12.First, the YUV switching unit 308 switches the output destination of thedecoder 301 to be the Y inverse transforming unit 302 (S301). It is tobe noted that the image decoding apparatus repeats the TU processes(S301 to S314) a number of times that there are TUs in a single CU sincethe processes are performed on all TUs within a single CU. Moreover, theimage decoding apparatus repeats the CU processes (S301 to S315) anumber of times that there are CUs in a single image since the processesare performed on all CUs within a single image.

Next, the decoder 301 decodes and outputs a bitstream to the Y inversetransforming unit 302 (S302). The Y inverse transforming unit 302performs an inverse transform process on Y, and outputs the inversetransformed result to the YUV combining unit 305 (S303).

Next, the adjacent block partitioning unit 309 determines whether thecurrent U block to be decoded as already been decoded (S304). If the Ublock has already been decoded (yes in S304), the processes for the Ublock and the V block (S305 to S313) are skipped. If not already decoded(no in S304), a YUV switching process (S305) is performed.

Specifically, if the U block has not already been decoded (no in S304),the YUV switching unit 308 switches the output of the decoder 301 to beinput to the U inverse transforming unit 303 (S305). Next, the decoder301 decodes and outputs a bitstream to the U inverse transforming unit303 (S306). The U inverse transforming unit 303 performs an inversetransform process on U, and outputs the inverse transformed result tothe adjacent block partitioning unit 309 (S307).

Next, the YUV switching unit 308 switches the output destination of thedecoder 301 to be the V inverse transforming unit 304 (S308). Thedecoder 301 then decodes and outputs a bitstream to the V inversetransforming unit 304 (S309). The V inverse transforming unit 304performs an inverse transform process on V, and outputs the inversetransformed result to the adjacent block partitioning unit 309 (S310).

Next, the adjacent block partitioning unit 309 determines whether thesize of the U within the TU is smaller than the smallest TU size (S311).If the size of the U is smaller than the smallest TU size (yes in S311),a U block partitioning process is performed (S312). If the size of the Uis not smaller than the smallest TU size (no in S311), the inversetransformed result of the input U and V are output to the YUV combiningunit 305 as is, and a YUV combining process is performed (S314).

If the size of the U is smaller than the smallest TU size (yes in S311),the adjacent block partitioning unit 309 partitions the inversetransformed U block in half heightwise and lengthwise resulting in afour partitioned parts, and outputs the result to the YUV combining unit305 (S312). The adjacent block partitioning unit 309 partitions theinverse transformed V block in half heightwise and lengthwise resultingin a four partitioned parts, and outputs the result to the YUV combiningunit 305 (S313).

The YUV combining unit 305 combines the Y, U, and V components andgenerates a TU pixel value (S314). The TU combining unit 306 combinesthe TU in the CU and generates the CU (S315). The CU combining unit 307combines the CU in an image and generates the image (S316).

(Result)

With the third embodiment, it is possible to decode U and V even beforeevery Y in the CU has been decoded, thereby eliminating the need tobuffer the U and V decoding result and allowing for a reduced buffermemory or register.

Moreover, even when the TU size is the smallest TU size and the numberof pixels in U or V is less than the number of pixels in Y, as is thecase in a 4:2:0 or 4:2:2 format, neither U nor V are smaller than thesmallest TU size. As a result, it is not necessary to provide an inversetransform circuit that is smaller than the smallest TU. Moreover, incontrast to a case in which Y had to be made larger than the smallest TUsize in an effort to keep U or V from being smaller than the smallestTU, with this configuration, Y can be made to be the smallest TU size,resulting in increased coding efficiency.

It is to be noted that in the third embodiment a 4:2:0 format is used,but a 4:2:2, 4:4:4, or different format may be used. When a 4:2:2 formatis used, the adjacent block partitioning unit 309 may partition the Uand V blocks heightwise into two parts instead of partitioning the U andV blocks into four parts (S312 and S313 in FIG. 12).

Moreover, in the third embodiment, the CU size and the TU size are inputexternally. However, the CU size and the TU size may be present withinthe bitstream. The decoder 301 may decode and obtain the CU size and theTU size.

Moreover, when the bitstream shown in FIG. 5 is used, the adjacent blockpartitioning unit 309 may determine whether the U block to be processedis present or not instead of determining whether the U block has alreadybeen decoded or not (S304 in FIG. 12). If the U block to be processed isnot present, the image decoding apparatus may skip the U and V processes(S305 to S314 in FIG. 12). With this, the image decoding apparatus candecode the bitstream shown in FIG. 5 just as it can the bitstream shownin FIG. 3.

Embodiment 4 (Configuration)

FIG. 13 shows a configuration of the image decoding apparatus accordingto the fourth embodiment. The image decoding apparatus is used whendecoding the bitstream coded by the image coding apparatus described inthe second embodiment. Here, only the YUV switching unit 308 isdescribed since the YUV switching unit 308 is different from the thirdembodiment.

The YUV switching unit 308 switches the output destination of thedecoder 301 according to the TU size and the specified smallest blocksize. Specifically, the YUV switching unit switches the output of thedecoder 301 on a per data unit basis to the Y inverse transforming unit302, the U inverse transforming unit 303, or the V inverse transformingunit 304. Here, the data unit is the larger of the TU size and thesmallest block size.

(Operation)

Next, the decoding flow will be described with reference to FIG. 14.First, the YUV switching unit 308 determines whether the TU size issmaller than the smallest block size (S401). If the TU size is smallerthan the smallest block size (yes in S401), a decoding determinationprocess (S411) is performed. If the TU size is not smaller than thesmallest block size (no in S401), a YUV switching process (S402) isperformed.

It is to be noted that the image decoding apparatus repeats the TUprocesses (S401 to S421) a number of times that there are TUs in asingle CU since the processes are performed on all TUs within a singleCU. Moreover, the image decoding apparatus repeats the CU processes(S401 to S422) a number of times that there are CUs in a single imagesince the processes are performed on all CUs within a single image.

After a determination has been made, when the TU size is not smallerthan the smallest block size (no in S401), the YUV switching unit 308switches the output destination of the decoder 301 to be the Y inversetransforming unit 302 (S402). Next, the decoder 301 decodes and outputsa bitstream to the Y inverse transforming unit 302 (S403). The Y inversetransforming unit 302 performs an inverse transform process on Y, andoutputs the inverse transformed result to the YUV combining unit 305(S404).

Next, the YUV switching unit 308 switches the output destination of thedecoder 301 to be the U inverse transforming unit 303 (S405). Thedecoder 301 decodes and outputs a bitstream to the U inversetransforming unit 303 (S406). The U inverse transforming unit 303performs an inverse transform process on U, and outputs the inversetransformed result to the YUV combining unit 305 (S407).

Next, the YUV switching unit 308 switches the output destination of thedecoder 301 to be the V inverse transforming unit 304 (S408). Thedecoder 301 then decodes and outputs a bitstream to the V inversetransforming unit 304 (S409). The V inverse transforming unit 304performs an inverse transform process on V, and outputs the inversetransformed result to the YUV combining unit 305 (S410).

If the TU size is smaller than the smallest block size (yes in S401),the YUV switching unit 308 determines whether the current block to bedecoded has already been decoded (S411). If the block has already beendecoded (yes in S411), a YUV combining process (S421) is performed. Ifnot already decoded (no in S411), a YUV switching process (S412) isperformed.

Specifically, when the block has not yet been decoded (no in S411), theYUV switching unit 308 switches the output destination of the decoder301 to be the Y inverse transforming unit 302 (S412). Next, the decoder301 decodes and outputs a bitstream to the Y inverse transforming unit302 (S413). It is to be noted that the image decoding apparatus repeatsthe Y processes (S413 to S414) a number of times that there are TUs in asmallest block since the processes are performed on all TUs within thesmallest block. The Y inverse transforming unit 302 performs an inversetransform process on Y, and outputs the inverse transformed result tothe YUV combining unit 305 (S414).

Next, the YUV switching unit 308 switches the output destination of thedecoder 301 to be the U inverse transforming unit 303 (S415). Thedecoder 301 decodes and outputs a bitstream to the U inversetransforming unit 303 (S416). It is to be noted that the image decodingapparatus repeats the U processes (S416 to S417) a number of times thatthere are TUs in a smallest block since the processes are performed onall TUs within the smallest block. The U inverse transforming unit 303performs an inverse transform process on U, and outputs the inversetransformed result to the YUV combining unit 305 (S417).

Next, the YUV switching unit 308 switches the output destination of thedecoder 301 to be the V inverse transforming unit 304 (S418). Thedecoder 301 then decodes and outputs a bitstream to the V inversetransforming unit 304 (S419). It is to be noted that the image decodingapparatus repeats the V processes (S419 to S420) a number of times thatthere are TUs in a smallest block since the processes are performed onall TUs within the smallest block. The V inverse transforming unit 304performs an inverse transform process on V, and outputs the inversetransformed result to the YUV combining unit 305 (S420).

After the processes have been performed on each of the Y, U, and V, theYUV combining unit 305 combines the Y, U, and V components and generatesa TU pixel value (S421). The TU combining unit 306 combines the TU inthe CU and generates the CU (S422). The CU combining unit 307 combinesthe CU in an image and generates the image (S423).

(Result)

With the fourth embodiment, it is possible to combine and processes theY, U, and V into respective multiple blocks and to output the outputimages in nearly one batch for each of the Y, U and V, therebyincreasing data transfer efficiency. Moreover, variation in the numberof pixels in a YUV set can be suppressed, and the computing unitoperating rate can be increased when parallel processing YUV data unitswith multiple computing units.

Embodiment 5

In the fifth embodiment, the characteristic configurations andprocedures of the first through fourth embodiments are described forconfirmation purposes. The configurations and procedures according tothe fifth embodiment correspond to the configuration and proceduresdescribed in the first through fourth embodiments. That is, the conceptsdescribed in the first through fourth embodiments include theconfigurations and procedures according to the fifth embodiment.

FIG. 15A is a block diagram illustrating a configuration of the imagecoding apparatus according to the fifth embodiment. The image codingapparatus 500 shown in FIG. 15A codes an image on a per coding unitbasis. Moreover, the image coding apparatus 500 includes a frequencytransform unit 501 and a coder 502. The frequency transform unit 501corresponds to, for example, the Y transforming unit 105, the Utransforming unit 106, and the V transforming unit 107 described in thefirst or second embodiment. The coder 502 corresponds to, for example,the coder 108 described in the first or second embodiment.

FIG. 15B is a flowchart which illustrates the operations of the imagecoding apparatus 500 shown in FIG. 15A.

First, the frequency transform unit 501 applies a frequency transform tothe luminance data and the chrominance data of the plurality oftransform units in a coding unit (S501). The coding unit includes aplurality of predetermined blocks. Each of the predetermined blockscorresponds to one or more transform units.

Next, the coder 502 codes the frequency transformed luminance data andthe frequency transformed chrominance data, and outputs a bitstreamthereof (S502). This bitstream is a bitstream of the luminance data andthe chrominance data combined on a per predetermined block basis.

With this, the memory or register for buffering the data of theplurality of transform units can be reduced. That is, am image isefficiently coded.

FIG. 16A is a block diagram illustrating a configuration of the imagedecoding apparatus according to the fifth embodiment. The image decodingapparatus 600 shown in FIG. 16A decodes an image on a per coding unitbasis. Moreover, the image decoding apparatus 600 includes a decoder 601and an inverse frequency transform unit 602. The decoder 601 correspondsto, for example, the decoder 301 described in the third or fourthembodiment. The inverse frequency transform unit 602 corresponds to, forexample, the Y inverse transforming unit 302, the U inverse transformingunit 303, and the V inverse transforming unit 304 described in the thirdor fourth embodiment.

FIG. 16B is a flowchart which illustrates the operations of the imagedecoding apparatus 600 shown in FIG. 16A.

First, the decoder 601 obtains a bitstream and decodes the luminancedata and the chrominance data (S601). This bitstream is a bitstream ofcombined (per predetermined block), frequency transformed, and codedluminance data and chrominance data of the plurality of transform unitsin a coding unit. Moreover, the coding unit includes a plurality ofpredetermined blocks. Each of the predetermined blocks corresponds toone or more transform units.

Next, the inverse frequency transform unit 602 applies an inversefrequency transform to the decoded luminance data and the decodedchrominance data (S602).

With this, the memory or register for buffering the data of theplurality of transform units can be reduced. That is, am image isefficiently decoded.

It is to be noted that, for example, each of the predetermined blocksmay correspond to a transform unit. Moreover, for example, each of thepredetermined blocks may correspond to a plurality of transform units ina block of a predetermined size, or to a transform unit of a size largerthan or equal to the predetermined size. The predetermined size may betwo times or four times the size of a predetermined smallest size of thetransform unit. The predetermined size may be changed based on the imageformat.

Moreover, for example, in the bitstream, in each of the predeterminedblocks, the luminance data may be arranged in succession and groupedtogether, and the chrominance data may be arranged in succession andgrouped together. Moreover, for example, in the bitstream, allchrominance data from a plurality of transform units in a predeterminedblock may be arranged after all luminance data from a plurality oftransform units in a predetermined block. Moreover, for example, in thebitstream, the luminance data and the chrominance data of a secondpredetermined block may be arranged after the luminance data and thechrominance data of a first predetermined block.

Moreover, for example, the frequency transform unit 501 may apply afrequency transform to the luminance data and the chrominance data on aper transform unit basis, and the inverse frequency transform unit 602may apply an inverse frequency transform to the luminance data and thechrominance data on a per transform unit basis. Moreover, for example,when the number of pixels in the chrominance data is fewer than thenumber of pixels in the luminance data, the frequency transform unit 501may apply a frequency transform to the chrominance data on a perpredetermined block basis, and the inverse frequency transform unit 602may apply an inverse frequency transform to the chrominance data on aper predetermined block basis.

Moreover, for example, the frequency transform unit 501 may combine thechrominance data from a plurality of transform units in a block that issmaller than or equal to a predetermined size, and may apply a frequencytransform to the combined chrominance data at once. The frequencytransform unit 501 may perform these kinds of processes when the size ofthe transform unit is the predetermined smallest size and the number ofpixels in the chrominance data in the transform unit is fewer than thenumber of pixels in the luminance data in the transform unit. The imagecoding apparatus 500 may include a combining unit which combines thechrominance data from a plurality of transform units.

Moreover, for example, the inverse frequency transform unit 602 may, atonce, apply an inverse frequency transform to the chrominance data froma plurality of transform units in a block that is smaller than or equalto a predetermined size. The inverse frequency transform unit 602 mayperform this kind of process when the size of the transform unit is thepredetermined smallest size and the number of pixels in the chrominancedata in the transform unit is fewer than the number of pixels in theluminance data in the transform unit. The image decoding apparatus 600may include a partitioning unit which partitions the chrominance data.

Moreover, for example, the image coding and decoding apparatus mayinclude the image coding apparatus 500 and the image decoding apparatus600. Moreover, the structural elements described in other embodimentsmay be added to the image coding apparatus 500 or the image decodingapparatus 600.

In each of the foregoing embodiments, each of the function blocks canusually be realized by means of MPU or memory, for example. Moreover,processing for each of the function blocks can usually be realized bymeans of software (program) stored on a storage medium such as ROM. Thesoftware may be distributed via downloading, or distributed on a storagemedium such as a CD-ROM. It is to be noted that each function block canalso be realized by means of hardware (dedicated circuit).

Moreover, the processing described in each of the embodiments may berealized by means of integrated processing using a single apparatus(system), or realized by means of decentralized processing using aplurality of apparatuses. Moreover, the computer which executes theforegoing program may be a single computer or a plurality of computers.In other words, integrated processing or decentralized processing may beperformed.

The present disclosure is not limited to the foregoing embodiments. Itgoes without saying that various types of modifications are acceptableand are also included scope of the present disclosure. For example, aprocess executed by a certain processing unit may be executed by adifferent processing unit. Moreover, the order of execution of theprocess may be changed, and a plurality of processes may be executed inparallel.

Each of the structural elements in each of the above-describedembodiments may be configured in the form of an exclusive hardwareproduct, or may be realized by executing a software program suitable forthe structural element. Each of the structural elements may be realizedby means of a program executing unit, such as a CPU and a processor,reading and executing the software program recorded on a recordingmedium such as a hard disk or a semiconductor memory. Here, the softwareprogram for realizing the image coding apparatus according to each ofthe embodiments is a program described below

That is, the program causes the computer to execute the image codingmethod of coding an image on a per coding unit basis that includes:applying a frequency transform to luminance data and chrominance data oftransform units in the coding unit including predetermined blocks eachcorresponding to one or more of the transform units; and coding theluminance data and the chrominance data to which the frequency transformhas been applied to generate a bitstream in which the luminance data andthe chrominance data are grouped on a per predetermined block basis.

Moreover, the program may cause the computer to execute the imagedecoding method of decoding an image on a per coding unit basis thatincludes: decoding luminance data and chrominance data of transformunits in the coding unit including predetermined blocks eachcorresponding to one or more of the transform units upon obtaining abitstream in which frequency transformed and coded luminance data andchrominance data are grouped on a per predetermined block basis; andapplying an inverse frequency transform to the decoded luminance dataand the decoded chrominance data.

The herein disclosed subject matter is to be considered descriptive andillustrative only, and the appended Claims are of a scope intended tocover and encompass not only the particular embodiments disclosed, butalso equivalent structures, methods, and/or uses.

Embodiment 6

The processing described in each of embodiments can be simplyimplemented in an independent computer system, by recording, in arecording medium, a program for implementing the configurations of themoving picture coding method (image coding method) and the movingpicture decoding method (image decoding method) described in each ofembodiments. The recording media may be any recording media as long asthe program can be recorded, such as a magnetic disk, an optical disk, amagnetic optical disk, an IC card, and a semiconductor memory.

Hereinafter, the applications to the moving picture coding method (imagecoding method) and the moving picture decoding method (image decodingmethod) described in each of embodiments and systems using thereof willbe described. The system has a feature of having an image coding anddecoding apparatus that includes an image coding apparatus using theimage coding method and an image decoding apparatus using the imagedecoding method. Other configurations in the system can be changed asappropriate depending on the cases.

FIG. 17 illustrates an overall configuration of a content providingsystem ex100 for implementing content distribution services. The areafor providing communication services is divided into cells of desiredsize, and base stations ex106, ex107, ex108, ex109, and ex110 which arefixed wireless stations are placed in each of the cells.

The content providing system ex100 is connected to devices, such as acomputer ex111, a personal digital assistant (PDA) ex112, a cameraex113, a cellular phone ex114 and a game machine ex115, via the Internetex101, an Internet service provider ex102, a telephone network ex104, aswell as the base stations ex106 to ex110, respectively.

However, the configuration of the content providing system ex100 is notlimited to the configuration shown in FIG. 17, and a combination inwhich any of the elements are connected is acceptable. In addition, eachdevice may be directly connected to the telephone network ex104, ratherthan via the base stations ex106 to ex110 which are the fixed wirelessstations. Furthermore, the devices may be interconnected to each othervia a short distance wireless communication and others.

The camera ex113, such as a digital video camera, is capable ofcapturing video. A camera ex116, such as a digital camera, is capable ofcapturing both still images and video. Furthermore, the cellular phoneex114 may be the one that meets any of the standards such as GlobalSystem for Mobile Communications (GSM) (registered trademark), CodeDivision Multiple Access (CDMA), Wideband-Code Division Multiple Access(W-CDMA), Long Term Evolution (LTE), and High Speed Packet Access(HSPA). Alternatively, the cellular phone ex114 may be a PersonalHandyphone System (PHS).

In the content providing system ex100, a streaming server ex103 isconnected to the camera ex113 and others via the telephone network ex104and the base station ex109, which enables distribution of images of alive show and others. In such a distribution, a content (for example,video of a music live show) captured by the user using the camera ex113is coded as described above in each of embodiments (i.e., the camerafunctions as the image coding apparatus according to an aspect of thepresent disclosure), and the coded content is transmitted to thestreaming server ex103. On the other hand, the streaming server ex103carries out stream distribution of the transmitted content data to theclients upon their requests. The clients include the computer ex111, thePDA ex112, the camera ex113, the cellular phone ex114, and the gamemachine ex115 that are capable of decoding the above-mentioned codeddata. Each of the devices that have received the distributed datadecodes and reproduces the coded data (i.e., functions as the imagedecoding apparatus according to an aspect of the present disclosure).

The captured data may be coded by the camera ex113 or the streamingserver ex103 that transmits the data, or the coding processes may beshared between the camera ex113 and the streaming server ex103.Similarly, the distributed data may be decoded by the clients or thestreaming server ex103, or the decoding processes may be shared betweenthe clients and the streaming server ex103. Furthermore, the data of thestill images and video captured by not only the camera ex113 but alsothe camera ex116 may be transmitted to the streaming server ex103through the computer ex111. The coding processes may be performed by thecamera ex116, the computer ex111, or the streaming server ex103, orshared among them.

Furthermore, the coding and decoding processes may be performed by anLSI ex500 generally included in each of the computer ex111 and thedevices. The LSI ex500 may be configured of a single chip or a pluralityof chips. Software for coding and decoding video may be integrated intosome type of a recording medium (such as a CD-ROM, a flexible disk, anda hard disk) that is readable by the computer ex111 and others, and thecoding and decoding processes may be performed using the software.Furthermore, when the cellular phone ex114 is equipped with a camera,the video data obtained by the camera may be transmitted. The video datais data coded by the LSI ex500 included in the cellular phone ex114.

Furthermore, the streaming server ex103 may be composed of servers andcomputers, and may decentralize data and process the decentralized data,record, or distribute data.

As described above, the clients may receive and reproduce the coded datain the content providing system ex100. In other words, the clients canreceive and decode information transmitted by the user, and reproducethe decoded data in real time in the content providing system ex100, sothat the user who does not have any particular right and equipment canimplement personal broadcasting.

Aside from the example of the content providing system ex100, at leastone of the moving picture coding apparatus (image coding apparatus) andthe moving picture decoding apparatus (image decoding apparatus)described in each of embodiments may be implemented in a digitalbroadcasting system ex200 illustrated in FIG. 18. More specifically, abroadcast station ex201 communicates or transmits, via radio waves to abroadcast satellite ex202, multiplexed data obtained by multiplexingaudio data and others onto video data. The video data is data coded bythe moving picture coding method described in each of embodiments (i.e.,data coded by the image coding apparatus according to an aspect of thepresent disclosure). Upon receipt of the multiplexed data, the broadcastsatellite ex202 transmits radio waves for broadcasting. Then, a home-useantenna ex204 with a satellite broadcast reception function receives theradio waves. Next, a device such as a television (receiver) ex300 and aset top box (STB) ex217 decodes the received multiplexed data, andreproduces the decoded data (i.e., functions as the image decodingapparatus according to an aspect of the present disclosure).

Furthermore, a reader/recorder ex218 (i) reads and decodes themultiplexed data recorded on a recording medium ex215, such as a DVD anda BD, or (i) codes video signals in the recording medium ex215, and insome cases, writes data obtained by multiplexing an audio signal on thecoded data. The reader/recorder ex218 can include the moving picturedecoding apparatus or the moving picture coding apparatus as shown ineach of embodiments. In this case, the reproduced video signals aredisplayed on the monitor ex219, and can be reproduced by another deviceor system using the recording medium ex215 on which the multiplexed datais recorded. It is also possible to implement the moving picturedecoding apparatus in the set top box ex217 connected to the cable ex203for a cable television or to the antenna ex204 for satellite and/orterrestrial broadcasting, so as to display the video signals on themonitor ex219 of the television ex300. The moving picture decodingapparatus may be implemented not in the set top box but in thetelevision ex300.

FIG. 19 illustrates the television (receiver) ex300 that uses the movingpicture coding method and the moving picture decoding method describedin each of embodiments. The television ex300 includes: a tuner ex301that obtains or provides multiplexed data obtained by multiplexing audiodata onto video data, through the antenna ex204 or the cable ex203, etc.that receives a broadcast; a modulation/demodulation unit ex302 thatdemodulates the received multiplexed data or modulates data intomultiplexed data to be supplied outside; and amultiplexing/demultiplexing unit ex303 that demultiplexes the modulatedmultiplexed data into video data and audio data, or multiplexes videodata and audio data coded by a signal processing unit ex306 into data.

The television ex300 further includes: a signal processing unit ex306including an audio signal processing unit ex304 and a video signalprocessing unit ex305 that decode audio data and video data and codeaudio data and video data, respectively (which function as the imagecoding apparatus and the image decoding apparatus according to theaspects of the present disclosure); and an output unit ex309 including aspeaker ex307 that provides the decoded audio signal, and a display unitex308 that displays the decoded video signal, such as a display.Furthermore, the television ex300 includes an interface unit ex317including an operation input unit ex312 that receives an input of a useroperation. Furthermore, the television ex300 includes a control unitex310 that controls overall each constituent element of the televisionex300, and a power supply circuit unit ex311 that supplies power to eachof the elements. Other than the operation input unit ex312, theinterface unit ex317 may include: a bridge ex313 that is connected to anexternal device, such as the reader/recorder ex218; a slot unit ex314for enabling attachment of the recording medium ex216, such as an SDcard; a driver ex315 to be connected to an external recording medium,such as a hard disk; and a modem ex316 to be connected to a telephonenetwork. Here, the recording medium ex216 can electrically recordinformation using a non-volatile/volatile semiconductor memory elementfor storage. The constituent elements of the television ex300 areconnected to each other through a synchronous bus.

First, the configuration in which the television ex300 decodesmultiplexed data obtained from outside through the antenna ex204 andothers and reproduces the decoded data will be described. In thetelevision ex300, upon a user operation through a remote controllerex220 and others, the multiplexing/demultiplexing unit ex303demultiplexes the multiplexed data demodulated by themodulation/demodulation unit ex302, under control of the control unitex310 including a CPU. Furthermore, the audio signal processing unitex304 decodes the demultiplexed audio data, and the video signalprocessing unit ex305 decodes the demultiplexed video data, using thedecoding method described in each of embodiments, in the televisionex300. The output unit ex309 provides the decoded video signal and audiosignal outside, respectively. When the output unit ex309 provides thevideo signal and the audio signal, the signals may be temporarily storedin buffers ex318 and ex319, and others so that the signals arereproduced in synchronization with each other. Furthermore, thetelevision ex300 may read multiplexed data not through a broadcast andothers but from the recording media ex215 and ex216, such as a magneticdisk, an optical disk, and a SD card. Next, a configuration in which thetelevision ex300 codes an audio signal and a video signal, and transmitsthe data outside or writes the data on a recording medium will bedescribed. In the television ex300, upon a user operation through theremote controller ex220 and others, the audio signal processing unitex304 codes an audio signal, and the video signal processing unit ex305codes a video signal, under control of the control unit ex310 using thecoding method described in each of embodiments. Themultiplexing/demultiplexing unit ex303 multiplexes the coded videosignal and audio signal, and provides the resulting signal outside. Whenthe multiplexing/demultiplexing unit ex303 multiplexes the video signaland the audio signal, the signals may be temporarily stored in thebuffers ex320 and ex321, and others so that the signals are reproducedin synchronization with each other. Here, the buffers ex318, ex319,ex320, and ex321 may be plural as illustrated, or at least one buffermay be shared in the television ex300. Furthermore, data may be storedin a buffer so that the system overflow and underfloor may be avoidedbetween the modulation/demodulation unit ex302 and themultiplexing/demultiplexing unit ex303, for example.

Furthermore, the television ex300 may include a configuration forreceiving an AV input from a microphone or a camera other than theconfiguration for obtaining audio and video data from a broadcast or arecording medium, and may code the obtained data. Although thetelevision ex300 can code, multiplex, and provide outside data in thedescription, it may be capable of only receiving, decoding, andproviding outside data but not the coding, multiplexing, and providingoutside data.

Furthermore, when the reader/recorder ex218 reads or writes multiplexeddata from or on a recording medium, one of the television ex300 and thereader/recorder ex218 may decode or code the multiplexed data, and thetelevision ex300 and the reader/recorder ex218 may share the decoding orcoding.

As an example, FIG. 20 illustrates a configuration of an informationreproducing/recording unit ex400 when data is read or written from or onan optical disk. The information reproducing/recording unit ex400includes constituent elements ex401, ex402, ex403, ex404, ex405, ex406,and ex407 to be described hereinafter. The optical head ex401 irradiatesa laser spot in a recording surface of the recording medium ex215 thatis an optical disk to write information, and detects reflected lightfrom the recording surface of the recording medium ex215 to read theinformation. The modulation recording unit ex402 electrically drives asemiconductor laser included in the optical head ex401, and modulatesthe laser light according to recorded data. The reproductiondemodulating unit ex403 amplifies a reproduction signal obtained byelectrically detecting the reflected light from the recording surfaceusing a photo detector included in the optical head ex401, anddemodulates the reproduction signal by separating a signal componentrecorded on the recording medium ex215 to reproduce the necessaryinformation. The buffer ex404 temporarily holds the information to berecorded on the recording medium ex215 and the information reproducedfrom the recording medium ex215. The disk motor ex405 rotates therecording medium ex215. The servo control unit ex406 moves the opticalhead ex401 to a predetermined information track while controlling therotation drive of the disk motor ex405 so as to follow the laser spot.The system control unit ex407 controls overall the informationreproducing/recording unit ex400. The reading and writing processes canbe implemented by the system control unit ex407 using variousinformation stored in the buffer ex404 and generating and adding newinformation as necessary, and by the modulation recording unit ex402,the reproduction demodulating unit ex403, and the servo control unitex406 that record and reproduce information through the optical headex401 while being operated in a coordinated manner. The system controlunit ex407 includes, for example, a microprocessor, and executesprocessing by causing a computer to execute a program for read andwrite.

Although the optical head ex401 irradiates a laser spot in thedescription, it may perform high-density recording using near fieldlight.

FIG. 21 illustrates the recording medium ex215 that is the optical disk.On the recording surface of the recording medium ex215, guide groovesare spirally formed, and an information track ex230 records, in advance,address information indicating an absolute position on the diskaccording to change in a shape of the guide grooves. The addressinformation includes information for determining positions of recordingblocks ex231 that are a unit for recording data. Reproducing theinformation track ex230 and reading the address information in anapparatus that records and reproduces data can lead to determination ofthe positions of the recording blocks. Furthermore, the recording mediumex215 includes a data recording area ex233, an inner circumference areaex232, and an outer circumference area ex234. The data recording areaex233 is an area for use in recording the user data. The innercircumference area ex232 and the outer circumference area ex234 that areinside and outside of the data recording area ex233, respectively arefor specific use except for recording the user data. The informationreproducing/recording unit 400 reads and writes coded audio, coded videodata, or multiplexed data obtained by multiplexing the coded audio andvideo data, from and on the data recording area ex233 of the recordingmedium ex215.

Although an optical disk having a layer, such as a DVD and a BD isdescribed as an example in the description, the optical disk is notlimited to such, and may be an optical disk having a multilayerstructure and capable of being recorded on a part other than thesurface. Furthermore, the optical disk may have a structure formultidimensional recording/reproduction, such as recording ofinformation using light of colors with different wavelengths in the sameportion of the optical disk and for recording information havingdifferent layers from various angles.

Furthermore, a car ex210 having an antenna ex205 can receive data fromthe satellite ex202 and others, and reproduce video on a display devicesuch as a car navigation system ex211 set in the car ex210, in thedigital broadcasting system ex200. Here, a configuration of the carnavigation system ex211 will be a configuration, for example, includinga GPS receiving unit from the configuration illustrated in FIG. 19. Thesame will be true for the configuration of the computer ex111, thecellular phone ex114, and others.

FIG. 22A illustrates the cellular phone ex114 that uses the movingpicture coding method and the moving picture decoding method describedin embodiments. The cellular phone ex114 includes: an antenna ex350 fortransmitting and receiving radio waves through the base station ex110; acamera unit ex365 capable of capturing moving and still images; and adisplay unit ex358 such as a liquid crystal display for displaying thedata such as decoded video captured by the camera unit ex365 or receivedby the antenna ex350. The cellular phone ex114 further includes: a mainbody unit including an operation key unit ex366; an audio output unitex357 such as a speaker for output of audio; an audio input unit ex356such as a microphone for input of audio; a memory unit ex367 for storingcaptured video or still pictures, recorded audio, coded or decoded dataof the received video, the still pictures, e-mails, or others; and aslot unit ex364 that is an interface unit for a recording medium thatstores data in the same manner as the memory unit ex367.

Next, an example of a configuration of the cellular phone ex114 will bedescribed with reference to FIG. 22B. In the cellular phone ex114, amain control unit ex360 designed to control overall each unit of themain body including the display unit ex358 as well as the operation keyunit ex366 is connected mutually, via a synchronous bus ex370, to apower supply circuit unit ex361, an operation input control unit ex362,a video signal processing unit ex355, a camera interface unit ex363, aliquid crystal display (LCD) control unit ex359, amodulation/demodulation unit ex352, a multiplexing/demultiplexing unitex353, an audio signal processing unit ex354, the slot unit ex364, andthe memory unit ex367.

When a call-end key or a power key is turned ON by a user's operation,the power supply circuit unit ex361 supplies the respective units withpower from a battery pack so as to activate the cell phone ex114.

In the cellular phone ex114, the audio signal processing unit ex354converts the audio signals collected by the audio input unit ex356 invoice conversation mode into digital audio signals under the control ofthe main control unit ex360 including a CPU, ROM, and RAM. Then, themodulation/demodulation unit ex352 performs spread spectrum processingon the digital audio signals, and the transmitting and receiving unitex351 performs digital-to-analog conversion and frequency conversion onthe data, so as to transmit the resulting data via the antenna ex350.Also, in the cellular phone ex114, the transmitting and receiving unitex351 amplifies the data received by the antenna ex350 in voiceconversation mode and performs frequency conversion and theanalog-to-digital conversion on the data. Then, themodulation/demodulation unit ex352 performs inverse spread spectrumprocessing on the data, and the audio signal processing unit ex354converts it into analog audio signals, so as to output them via theaudio output unit ex357.

Furthermore, when an e-mail in data communication mode is transmitted,text data of the e-mail inputted by operating the operation key unitex366 and others of the main body is sent out to the main control unitex360 via the operation input control unit ex362. The main control unitex360 causes the modulation/demodulation unit ex352 to perform spreadspectrum processing on the text data, and the transmitting and receivingunit ex351 performs the digital-to-analog conversion and the frequencyconversion on the resulting data to transmit the data to the basestation ex110 via the antenna ex350. When an e-mail is received,processing that is approximately inverse to the processing fortransmitting an e-mail is performed on the received data, and theresulting data is provided to the display unit ex358.

When video, still images, or video and audio in data communication modeis or are transmitted, the video signal processing unit ex355 compressesand codes video signals supplied from the camera unit ex365 using themoving picture coding method shown in each of embodiments (i.e.,functions as the image coding apparatus according to the aspect of thepresent disclosure), and transmits the coded video data to themultiplexing/demultiplexing unit ex353. In contrast, during when thecamera unit ex365 captures video, still images, and others, the audiosignal processing unit ex354 codes audio signals collected by the audioinput unit ex356, and transmits the coded audio data to themultiplexing/demultiplexing unit ex353.

The multiplexing/demultiplexing unit ex353 multiplexes the coded videodata supplied from the video signal processing unit ex355 and the codedaudio data supplied from the audio signal processing unit ex354, using apredetermined method. Then, the modulation/demodulation unit(modulation/demodulation circuit unit) ex352 performs spread spectrumprocessing on the multiplexed data, and the transmitting and receivingunit ex351 performs digital-to-analog conversion and frequencyconversion on the data so as to transmit the resulting data via theantenna ex350.

When receiving data of a video file which is linked to a Web page andothers in data communication mode or when receiving an e-mail with videoand/or audio attached, in order to decode the multiplexed data receivedvia the antenna ex350, the multiplexing/demultiplexing unit ex353demultiplexes the multiplexed data into a video data bit stream and anaudio data bit stream, and supplies the video signal processing unitex355 with the coded video data and the audio signal processing unitex354 with the coded audio data, through the synchronous bus ex370. Thevideo signal processing unit ex355 decodes the video signal using amoving picture decoding method corresponding to the moving picturecoding method shown in each of embodiments (i.e., functions as the imagedecoding apparatus according to the aspect of the present disclosure),and then the display unit ex358 displays, for instance, the video andstill images included in the video file linked to the Web page via theLCD control unit ex359. Furthermore, the audio signal processing unitex354 decodes the audio signal, and the audio output unit ex357 providesthe audio.

Furthermore, similarly to the television ex300, a terminal such as thecellular phone ex114 probably have 3 types of implementationconfigurations including not only (i) a transmitting and receivingterminal including both a coding apparatus and a decoding apparatus, butalso (ii) a transmitting terminal including only a coding apparatus and(iii) a receiving terminal including only a decoding apparatus. Althoughthe digital broadcasting system ex200 receives and transmits themultiplexed data obtained by multiplexing audio data onto video data inthe description, the multiplexed data may be data obtained bymultiplexing not audio data but character data related to video ontovideo data, and may be not multiplexed data but video data itself.

As such, the moving picture coding method and the moving picturedecoding method in each of embodiments can be used in any of the devicesand systems described. Thus, the advantages described in each ofembodiments can be obtained.

Furthermore, various modifications and revisions can be made in any ofthe embodiments in the present disclosure.

Embodiment 7

Video data can be generated by switching, as necessary, between (i) themoving picture coding method or the moving picture coding apparatusshown in each of embodiments and (ii) a moving picture coding method ora moving picture coding apparatus in conformity with a differentstandard, such as MPEG-2, MPEG-4 AVC, and VC-1.

Here, when a plurality of video data that conforms to the differentstandards is generated and is then decoded, the decoding methods need tobe selected to conform to the different standards. However, since towhich standard each of the plurality of the video data to be decodedconform cannot be detected, there is a problem that an appropriatedecoding method cannot be selected.

In order to solve the problem, multiplexed data obtained by multiplexingaudio data and others onto video data has a structure includingidentification information indicating to which standard the video dataconforms. The specific structure of the multiplexed data including thevideo data generated in the moving picture coding method and by themoving picture coding apparatus shown in each of embodiments will behereinafter described. The multiplexed data is a digital stream in theMPEG-2 Transport Stream format.

FIG. 23 illustrates a structure of the multiplexed data. As illustratedin FIG. 23, the multiplexed data can be obtained by multiplexing atleast one of a video stream, an audio stream, a presentation graphicsstream (PG), and an interactive graphics stream. The video streamrepresents primary video and secondary video of a movie, the audiostream (IG) represents a primary audio part and a secondary audio partto be mixed with the primary audio part, and the presentation graphicsstream represents subtitles of the movie. Here, the primary video isnormal video to be displayed on a screen, and the secondary video isvideo to be displayed on a smaller window in the primary video.Furthermore, the interactive graphics stream represents an interactivescreen to be generated by arranging the GUI components on a screen. Thevideo stream is coded in the moving picture coding method or by themoving picture coding apparatus shown in each of embodiments, or in amoving picture coding method or by a moving picture coding apparatus inconformity with a conventional standard, such as MPEG-2, MPEG-4 AVC, andVC-1. The audio stream is coded in accordance with a standard, such asDolby-AC-3, Dolby Digital Plus, MLP, DTS, DTS-HD, and linear PCM.

Each stream included in the multiplexed data is identified by PID. Forexample, 0x1011 is allocated to the video stream to be used for video ofa movie, 0x1100 to 0x111F are allocated to the audio streams, 0x1200 to0x121F are allocated to the presentation graphics streams, 0x1400 to0x141F are allocated to the interactive graphics streams, 0x1B00 to0x1B1F are allocated to the video streams to be used for secondary videoof the movie, and 0x1A00 to 0x1A1F are allocated to the audio streams tobe used for the secondary audio to be mixed with the primary audio.

FIG. 24 schematically illustrates how data is multiplexed. First, avideo stream ex235 composed of video frames and an audio stream ex238composed of audio frames are transformed into a stream of PES packetsex236 and a stream of PES packets ex239, and further into TS packetsex237 and TS packets ex240, respectively. Similarly, data of apresentation graphics stream ex241 and data of an interactive graphicsstream ex244 are transformed into a stream of PES packets ex242 and astream of PES packets ex245, and further into TS packets ex243 and TSpackets ex246, respectively. These TS packets are multiplexed into astream to obtain multiplexed data ex247.

FIG. 25 illustrates how a video stream is stored in a stream of PESpackets in more detail. The first bar in FIG. 25 shows a video framestream in a video stream. The second bar shows the stream of PESpackets. As indicated by arrows denoted as yy1, yy2, yy3, and yy4 inFIG. 25, the video stream is divided into pictures as I pictures, Bpictures, and P pictures each of which is a video presentation unit, andthe pictures are stored in a payload of each of the PES packets. Each ofthe PES packets has a PES header, and the PES header stores aPresentation Time-Stamp (PTS) indicating a display time of the picture,and a Decoding Time-Stamp (DTS) indicating a decoding time of thepicture.

FIG. 26 illustrates a format of TS packets to be finally written on themultiplexed data. Each of the TS packets is a 188-byte fixed lengthpacket including a 4-byte TS header having information, such as a PIDfor identifying a stream and a 184-byte TS payload for storing data. ThePES packets are divided, and stored in the TS payloads, respectively.When a BD ROM is used, each of the TS packets is given a 4-byteTP_Extra_Header, thus resulting in 192-byte source packets. The sourcepackets are written on the multiplexed data. The TP_Extra_Header storesinformation such as an Arrival_Time_Stamp (ATS). The ATS shows atransfer start time at which each of the TS packets is to be transferredto a PID filter. The source packets are arranged in the multiplexed dataas shown at the bottom of FIG. 26. The numbers incrementing from thehead of the multiplexed data are called source packet numbers (SPNs).

Each of the TS packets included in the multiplexed data includes notonly streams of audio, video, subtitles and others, but also a ProgramAssociation Table (PAT), a Program Map Table (PMT), and a Program ClockReference (PCR). The PAT shows what a PID in a PMT used in themultiplexed data indicates, and a PID of the PAT itself is registered aszero. The PMT stores PIDs of the streams of video, audio, subtitles andothers included in the multiplexed data, and attribute information ofthe streams corresponding to the PIDs. The PMT also has variousdescriptors relating to the multiplexed data. The descriptors haveinformation such as copy control information showing whether copying ofthe multiplexed data is permitted or not. The PCR stores STC timeinformation corresponding to an ATS showing when the PCR packet istransferred to a decoder, in order to achieve synchronization between anArrival Time Clock (ATC) that is a time axis of ATSs, and an System TimeClock (STC) that is a time axis of PTSs and DTSs.

FIG. 27 illustrates the data structure of the PMT in detail. A PMTheader is disposed at the top of the PMT. The PMT header describes thelength of data included in the PMT and others. A plurality ofdescriptors relating to the multiplexed data is disposed after the PMTheader. Information such as the copy control information is described inthe descriptors. After the descriptors, a plurality of pieces of streaminformation relating to the streams included in the multiplexed data isdisposed. Each piece of stream information includes stream descriptorseach describing information, such as a stream type for identifying acompression codec of a stream, a stream PID, and stream attributeinformation (such as a frame rate or an aspect ratio). The streamdescriptors are equal in number to the number of streams in themultiplexed data.

When the multiplexed data is recorded on a recording medium and others,it is recorded together with multiplexed data information files.

Each of the multiplexed data information files is management informationof the multiplexed data as shown in FIG. 28. The multiplexed datainformation files are in one to one correspondence with the multiplexeddata, and each of the files includes multiplexed data information,stream attribute information, and an entry map.

As illustrated in FIG. 28, the multiplexed data information includes asystem rate, a reproduction start time, and a reproduction end time. Thesystem rate indicates the maximum transfer rate at which a system targetdecoder to be described later transfers the multiplexed data to a PIDfilter. The intervals of the ATSs included in the multiplexed data areset to not higher than a system rate. The reproduction start timeindicates a PTS in a video frame at the head of the multiplexed data. Aninterval of one frame is added to a PTS in a video frame at the end ofthe multiplexed data, and the PTS is set to the reproduction end time.

As shown in FIG. 29, a piece of attribute information is registered inthe stream attribute information, for each PID of each stream includedin the multiplexed data. Each piece of attribute information hasdifferent information depending on whether the corresponding stream is avideo stream, an audio stream, a presentation graphics stream, or aninteractive graphics stream. Each piece of video stream attributeinformation carries information including what kind of compression codecis used for compressing the video stream, and the resolution, aspectratio and frame rate of the pieces of picture data that is included inthe video stream. Each piece of audio stream attribute informationcarries information including what kind of compression codec is used forcompressing the audio stream, how many channels are included in theaudio stream, which language the audio stream supports, and how high thesampling frequency is. The video stream attribute information and theaudio stream attribute information are used for initialization of adecoder before the player plays back the information.

In the present embodiment, the multiplexed data to be used is of astream type included in the PMT. Furthermore, when the multiplexed datais recorded on a recording medium, the video stream attributeinformation included in the multiplexed data information is used. Morespecifically, the moving picture coding method or the moving picturecoding apparatus described in each of embodiments includes a step or aunit for allocating unique information indicating video data generatedby the moving picture coding method or the moving picture codingapparatus in each of embodiments, to the stream type included in the PMTor the video stream attribute information. With the configuration, thevideo data generated by the moving picture coding method or the movingpicture coding apparatus described in each of embodiments can bedistinguished from video data that conforms to another standard.

Furthermore, FIG. 30 illustrates steps of the moving picture decodingmethod according to the present embodiment. In Step exS100, the streamtype included in the PMT or the video stream attribute informationincluded in the multiplexed data information is obtained from themultiplexed data. Next, in Step exS101, it is determined whether or notthe stream type or the video stream attribute information indicates thatthe multiplexed data is generated by the moving picture coding method orthe moving picture coding apparatus in each of embodiments. When it isdetermined that the stream type or the video stream attributeinformation indicates that the multiplexed data is generated by themoving picture coding method or the moving picture coding apparatus ineach of embodiments, in Step exS102, decoding is performed by the movingpicture decoding method in each of embodiments. Furthermore, when thestream type or the video stream attribute information indicatesconformance to the conventional standards, such as MPEG-2, MPEG-4 AVC,and VC-1, in Step exS103, decoding is performed by a moving picturedecoding method in conformity with the conventional standards.

As such, allocating a new unique value to the stream type or the videostream attribute information enables determination whether or not themoving picture decoding method or the moving picture decoding apparatusthat is described in each of embodiments can perform decoding. Even whenmultiplexed data that conforms to a different standard is input, anappropriate decoding method or apparatus can be selected. Thus, itbecomes possible to decode information without any error. Furthermore,the moving picture coding method or apparatus, or the moving picturedecoding method or apparatus in the present embodiment can be used inthe devices and systems described above.

Embodiment 8

Each of the moving picture coding method, the moving picture codingapparatus, the moving picture decoding method, and the moving picturedecoding apparatus in each of embodiments is typically achieved in theform of an integrated circuit or a Large Scale Integrated (LSI) circuit.As an example of the LSI, FIG. 31 illustrates a configuration of the LSIex500 that is made into one chip. The LSI ex500 includes elements ex501,ex502, ex503, ex504, ex505, ex506, ex507, ex508, and ex509 to bedescribed below, and the elements are connected to each other through abus ex510. The power supply circuit unit ex505 is activated by supplyingeach of the elements with power when the power supply circuit unit ex505is turned on.

For example, when coding is performed, the LSI ex500 receives an AVsignal from a microphone ex117, a camera ex113, and others through an AVIO ex509 under control of a control unit ex501 including a CPU ex502, amemory controller ex503, a stream controller ex504, and a drivingfrequency control unit ex512. The received AV signal is temporarilystored in an external memory ex511, such as an SDRAM. Under control ofthe control unit ex501, the stored data is segmented into data portionsaccording to the processing amount and speed to be transmitted to asignal processing unit ex507. Then, the signal processing unit ex507codes an audio signal and/or a video signal. Here, the coding of thevideo signal is the coding described in each of embodiments.Furthermore, the signal processing unit ex507 sometimes multiplexes thecoded audio data and the coded video data, and a stream IO ex506provides the multiplexed data outside. The provided multiplexed data istransmitted to the base station ex107, or written on the recordingmedium ex215. When data sets are multiplexed, the data should betemporarily stored in the buffer ex508 so that the data sets aresynchronized with each other.

Although the memory ex511 is an element outside the LSI ex500, it may beincluded in the LSI ex500. The buffer ex508 is not limited to onebuffer, but may be composed of buffers. Furthermore, the LSI ex500 maybe made into one chip or a plurality of chips.

Furthermore, although the control unit ex501 includes the CPU ex502, thememory controller ex503, the stream controller ex504, the drivingfrequency control unit ex512, the configuration of the control unitex501 is not limited to such. For example, the signal processing unitex507 may further include a CPU. Inclusion of another CPU in the signalprocessing unit ex507 can improve the processing speed. Furthermore, asanother example, the CPU ex502 may serve as or be a part of the signalprocessing unit ex507, and, for example, may include an audio signalprocessing unit. In such a case, the control unit ex501 includes thesignal processing unit ex507 or the CPU ex502 including a part of thesignal processing unit ex507.

The name used here is LSI, but it may also be called IC, system LSI,super LSI, or ultra LSI depending on the degree of integration.

Moreover, ways to achieve integration are not limited to the LSI, and aspecial circuit or a general purpose processor and so forth can alsoachieve the integration. Field Programmable Gate Array (FPGA) that canbe programmed after manufacturing LSIs or a reconfigurable processorthat allows re-configuration of the connection or configuration of anLSI can be used for the same purpose.

In the future, with advancement in semiconductor technology, a brand-newtechnology may replace LSI. The functional blocks can be integratedusing such a technology. The possibility is that the present disclosureis applied to biotechnology.

Embodiment 9

When video data generated in the moving picture coding method or by themoving picture coding apparatus described in each of embodiments isdecoded, compared to when video data that conforms to a conventionalstandard, such as MPEG-2, MPEG-4 AVC, and VC-1 is decoded, theprocessing amount probably increases. Thus, the LSI ex500 needs to beset to a driving frequency higher than that of the CPU ex502 to be usedwhen video data in conformity with the conventional standard is decoded.However, when the driving frequency is set higher, there is a problemthat the power consumption increases.

In order to solve the problem, the moving picture decoding apparatus,such as the television ex300 and the LSI ex500 is configured todetermine to which standard the video data conforms, and switch betweenthe driving frequencies according to the determined standard. FIG. 32illustrates a configuration ex800 in the present embodiment. A drivingfrequency switching unit ex803 sets a driving frequency to a higherdriving frequency when video data is generated by the moving picturecoding method or the moving picture coding apparatus described in eachof embodiments. Then, the driving frequency switching unit ex803instructs a decoding processing unit ex801 that executes the movingpicture decoding method described in each of embodiments to decode thevideo data. When the video data conforms to the conventional standard,the driving frequency switching unit ex803 sets a driving frequency to alower driving frequency than that of the video data generated by themoving picture coding method or the moving picture coding apparatusdescribed in each of embodiments. Then, the driving frequency switchingunit ex803 instructs the decoding processing unit ex802 that conforms tothe conventional standard to decode the video data.

More specifically, the driving frequency switching unit ex803 includesthe CPU ex502 and the driving frequency control unit ex512 in FIG. 31.Here, each of the decoding processing unit ex801 that executes themoving picture decoding method described in each of embodiments and thedecoding processing unit ex802 that conforms to the conventionalstandard corresponds to the signal processing unit ex507 in FIG. 31. TheCPU ex502 determines to which standard the video data conforms. Then,the driving frequency control unit ex512 determines a driving frequencybased on a signal from the CPU ex502. Furthermore, the signal processingunit ex507 decodes the video data based on the signal from the CPUex502. For example, the identification information described inEmbodiment 7 is probably used for identifying the video data. Theidentification information is not limited to the one described inEmbodiment 7 but may be any information as long as the informationindicates to which standard the video data conforms. For example, whenwhich standard video data conforms to can be determined based on anexternal signal for determining that the video data is used for atelevision or a disk, etc., the determination may be made based on suchan external signal. Furthermore, the CPU ex502 selects a drivingfrequency based on, for example, a look-up table in which the standardsof the video data are associated with the driving frequencies as shownin FIG. 34. The driving frequency can be selected by storing the look-uptable in the buffer ex508 and in an internal memory of an LSI, and withreference to the look-up table by the CPU ex502.

FIG. 33 illustrates steps for executing a method in the presentembodiment. First, in Step exS200, the signal processing unit ex507obtains identification information from the multiplexed data. Next, inStep exS201, the CPU ex502 determines whether or not the video data isgenerated by the coding method and the coding apparatus described ineach of embodiments, based on the identification information. When thevideo data is generated by the moving picture coding method and themoving picture coding apparatus described in each of embodiments, inStep exS202, the CPU ex502 transmits a signal for setting the drivingfrequency to a higher driving frequency to the driving frequency controlunit ex512. Then, the driving frequency control unit ex512 sets thedriving frequency to the higher driving frequency. On the other hand,when the identification information indicates that the video dataconforms to the conventional standard, such as MPEG-2, MPEG-4 AVC, andVC-1, in Step exS203, the CPU ex502 transmits a signal for setting thedriving frequency to a lower driving frequency to the driving frequencycontrol unit ex512. Then, the driving frequency control unit ex512 setsthe driving frequency to the lower driving frequency than that in thecase where the video data is generated by the moving picture codingmethod and the moving picture coding apparatus described in each ofembodiment.

Furthermore, along with the switching of the driving frequencies, thepower conservation effect can be improved by changing the voltage to beapplied to the LSI ex500 or an apparatus including the LSI ex500. Forexample, when the driving frequency is set lower, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set to a voltage lower than that in the case where the drivingfrequency is set higher.

Furthermore, when the processing amount for decoding is larger, thedriving frequency may be set higher, and when the processing amount fordecoding is smaller, the driving frequency may be set lower as themethod for setting the driving frequency. Thus, the setting method isnot limited to the ones described above. For example, when theprocessing amount for decoding video data in conformity with MPEG-4 AVCis larger than the processing amount for decoding video data generatedby the moving picture coding method and the moving picture codingapparatus described in each of embodiments, the driving frequency isprobably set in reverse order to the setting described above.

Furthermore, the method of setting the driving frequency is not limitedto the method of setting the driving frequency lower. For example, whenthe identification information indicates that the video data isgenerated by the moving picture coding method and the moving picturecoding apparatus described in each of embodiments, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set higher. When the identification information indicates thatthe video data conforms to the conventional standard, such as MPEG-2,MPEG-4 AVC, and VC-1, the voltage to be applied to the LSI ex500 or theapparatus including the LSI ex500 is probably set lower. As anotherexample, when the identification information indicates that the videodata is generated by the moving picture coding method and the movingpicture coding apparatus described in each of embodiments, the drivingof the CPU ex502 does not probably have to be suspended. When theidentification information indicates that the video data conforms to theconventional standard, such as MPEG-2, MPEG-4 AVC, and VC-1, the drivingof the CPU ex502 is probably suspended at a given time because the CPUex502 has extra processing capacity. Even when the identificationinformation indicates that the video data is generated by the movingpicture coding method and the moving picture coding apparatus describedin each of embodiments, in the case where the CPU ex502 has extraprocessing capacity, the driving of the CPU ex502 is probably suspendedat a given time. In such a case, the suspending time is probably setshorter than that in the case where when the identification informationindicates that the video data conforms to the conventional standard,such as MPEG-2, MPEG-4 AVC, and VC-1.

Accordingly, the power conservation effect can be increased by switchingbetween the driving frequencies in accordance with the standard to whichthe video data conforms. Furthermore, when the LSI ex500 or theapparatus including the LSI ex500 is driven using a battery, the batterylife can be extended with the power conservation effect.

Embodiment 10

There are cases where a plurality of video data that conforms todifferent standards, is provided to the devices and systems, such as atelevision and a cellular phone. In order to enable decoding theplurality of video data that conforms to the different standards, thesignal processing unit ex507 of the LSI ex500 needs to conform to thedifferent standards. However, the problems of increase in the scale ofthe circuit of the LSI ex500 and increase in the cost arise with theindividual use of the signal processing units ex507 that conform to therespective standards.

In order to solve the problem, what is conceived is a configuration inwhich the decoding processing unit for implementing the moving picturedecoding method described in each of embodiments and the decodingprocessing unit that conforms to the conventional standard, such asMPEG-2, MPEG-4 AVC, and VC-1 are partly shared. Ex900 in FIG. 35A showsan example of the configuration. For example, the moving picturedecoding method described in each of embodiments and the moving picturedecoding method that conforms to MPEG-4 AVC have, partly in common, thedetails of processing, such as entropy coding, inverse quantization,deblocking filtering, and motion compensated prediction. The details ofprocessing to be shared probably include use of a decoding processingunit ex902 that conforms to MPEG-4 AVC. In contrast, a dedicateddecoding processing unit ex901 is probably used for other processingunique to an aspect of the present disclosure. Since the aspect of thepresent disclosure is characterized by entropy decoding in particular,for example, the dedicated decoding processing unit ex901 is used forentropy decoding. Otherwise, the decoding processing unit is probablyshared for one of the inverse quantization, deblocking filtering, andmotion compensation, or all of the processing. The decoding processingunit for implementing the moving picture decoding method described ineach of embodiments may be shared for the processing to be shared, and adedicated decoding processing unit may be used for processing unique tothat of MPEG-4 AVC.

Furthermore, ex1000 in FIG. 35B shows another example in that processingis partly shared. This example uses a configuration including adedicated decoding processing unit ex1001 that supports the processingunique to an aspect of the present disclosure, a dedicated decodingprocessing unit ex1002 that supports the processing unique to anotherconventional standard, and a decoding processing unit ex1003 thatsupports processing to be shared between the moving picture decodingmethod according to the aspect of the present disclosure and theconventional moving picture decoding method. Here, the dedicateddecoding processing units ex1001 and ex1002 are not necessarilyspecialized for the processing according to the aspect of the presentdisclosure and the processing of the conventional standard,respectively, and may be the ones capable of implementing generalprocessing. Furthermore, the configuration of the present embodiment canbe implemented by the LSI ex500.

As such, reducing the scale of the circuit of an LSI and reducing thecost are possible by sharing the decoding processing unit for theprocessing to be shared between the moving picture decoding methodaccording to the aspect of the present disclosure and the moving picturedecoding method in conformity with the conventional standard.

INDUSTRIAL APPLICABILITY

The image coding method and the image decoding method according to thepresent disclosure are useful in various image coding apparatuses andimage decoding apparatuses such as video cameras, cellular phones withcameras, DVD recorders, and televisions, for example.

1. An image decoding method of decoding an image on a per coding unitbasis, the method comprising: decoding luminance data and chrominancedata of transform units in the coding unit including predeterminedblocks each corresponding to one or more of the transform units, thedecoding including obtaining a bitstream, and the luminance data and thechrominance data being data to which a frequency transform has beenapplied and which has been coded and grouped in the bitstream on a perpredetermined block basis; and applying an inverse frequency transformto the decoded luminance data and the decoded chrominance data.
 2. Theimage decoding method according to claim 1, wherein each of thepredetermined blocks corresponds to transform units in a block of apredetermined size, or to a transform unit of a size greater than orequal to the predetermined size, and in the decoding, the bitstream inwhich the luminance data and the chrominance data are grouped on a perpredetermined block basis is obtained, and the luminance data and thechrominance data are decoded.
 3. The image decoding method according toclaim 1, wherein in the applying: the inverse frequency transform isapplied to the luminance data on a per transform unit basis; when atotal number of pixels of the chrominance data and a total number ofpixels of the luminance data are equal, the inverse frequency transformis applied to the chrominance data on a per transform unit basis; andwhen the total number of pixels of the chrominance data is less than thetotal number of pixels of the luminance data, the inverse frequencytransform is applied to the chrominance data on a per predeterminedblock basis.
 4. The image decoding method according to claim 1, whereinin the applying, the inverse frequency transform is applied to, fromamong the chrominance data of the transform units in the coding unit,chrominance data of transform units in a block of a size that is smallerthan or equal to the predetermined size in one inverse frequencytransform.
 5. The image decoding method according to claim 1, wherein inthe applying, when a size of one of the transform units is apredetermined smallest size and in the transform unit a total number ofpixels of the chrominance data is less than a total number of pixels ofthe luminance data, the inverse frequency transform is applied to, fromamong the chrominance data of the transform units in the coding unit,chrominance data of transform units in a block including the transformunit in one inverse frequency transform.
 6. The image decoding methodaccording to claim 1, wherein in the decoding, the bitstream is obtainedin which, in one of the predetermined blocks, chrominance data of alltransform units follows luminance data of all the transform units, andthe luminance data and the chrominance data of the transform units inthe predetermined block are decoded.
 7. The image decoding methodaccording to claim 1, wherein each of the predetermined blockscorresponds to transform units in a block of a predetermined size, or toa transform unit of a size greater than or equal to the predeterminedsize, in the decoding, the bitstream in which the luminance data and thechrominance data are grouped on a per predetermined block basis isobtained, and the luminance data and the chrominance data are decoded,and in the applying, the inverse frequency transform is applied to theluminance data and the chrominance data on a per transform unit basis.8. The image decoding method according to claim 1, wherein each of thepredetermined blocks corresponds to a different one of the transformunits, in the decoding, the bitstream in which the luminance data andthe chrominance data are grouped on a per transform unit basis isobtained, and the luminance data and the chrominance data are decoded,and in the applying, the inverse frequency transform is applied to theluminance data and the chrominance data on a per transform unit basis.9. An image decoding apparatus which decodes an image on a per codingunit basis, the image decoding apparatus comprising: a decoder which (i)obtains a bitstream in which frequency transformed and coded luminancedata and chrominance data are grouped on a per predetermined blockbasis, and (ii) decodes the luminance data and the chrominance data oftransform units in the coding unit including predetermined blocks eachcorresponding to one or more of the transform units; and an inversefrequency transform unit configured to apply an inverse frequencytransform to the decoded luminance data and the decoded chrominancedata.